Using the powerful James Webb Space Telescope (JWST), astronomers have made a significant discovery in the early universe. They identified a supermassive black hole, named “BiRD,” which formed during a period known as “cosmic noon,” approximately 4 billion years after the Big Bang. This finding could enhance our understanding of how supermassive black holes grow to immense sizes, often millions to billions of times heavier than the sun.
BiRD is part of a set of objects referred to as “little red dots,” which the JWST has been revealing. This particular black hole possesses a mass estimated at about 100 million times that of the sun. The designation “Big Red Dot” reflects both its substantial size and the captivating nature of the discovery. Black holes themselves do not emit light; their gravitational pull traps any nearby light. Nonetheless, when surrounded by matter, they can produce bright quasars, which are visible from great distances. The light from BiRD has traveled for 10 billion years to reach Earth.
The discovery team, affiliated with the National Institute for Astrophysics (INAF), located BiRD near the known quasar J1030+0524, located approximately 12.5 billion light-years from Earth. This area of the sky has been frequently studied, yet BiRD’s unusual light source was detected while analyzing data from the JWST’s Near-Infrared Camera (NIRCam).
Team leader and INAF research fellow, Federica Loiacono, explained the process: “Starting from the calibrated images, a catalog of the sources present in the field was developed. It was there that we noticed BiRD: a bright, point-like object, which, however, was not a star and did not appear in the existing X-ray and radio catalogs.” Further analysis of BiRD’s spectrum revealed important chemical signatures, including hydrogen and helium.
The findings included clear signals of ionized hydrogen, particularly the Paschen gamma line, which indicates the presence of this element. “These details allowed us to estimate the distance to BiRD,” Loiacono added. The analysis concluded that BiRD is relatively close compared to other known little red dots.
Little red dots are characterized by their compact nature and unique spectroscopic properties, leading to various theories about their origins. One popular hypothesis suggests that these objects are feeding and growing supermassive black holes. A challenge to this idea is the lack of strong X-ray emissions typically associated with such black holes. Instead, the little red dots, including BiRD, may represent massive black hole “seeds,” still enveloped in gas and dust that absorb high-energy X-rays while allowing lower-energy infrared light to escape.
Interestingly, BiRD stands out among its peers. Loiacono noted, “Before BiRD, only two other little red dots with the same spectral characteristics, including helium lines and Paschen gamma rays, were known at this same cosmic distance.” The similarities in spectral properties suggest that BiRD belongs to the same category as these intriguing celestial objects.
This research not only highlights the discovery of BiRD but also has implications for our understanding of the growth and evolution of supermassive black holes. Traditionally, scientists believed these objects would begin to fade as cosmic noon approached, around 11 billion years ago. However, the team conducted calculations revealing that little red dots remained prevalent during this epoch.
“The challenge now is to extend the study to a larger number of nearby little red dots, which we can examine in greater detail than distant ones, to build a more complete picture,” Loiacono concluded. The findings were published on October 30, 2023, in the journal Astronomy & Astrophysics, marking a promising step in the exploration of the universe’s early history. The JWST continues to unveil mysteries of the cosmos, revealing objects previously unimagined and opening new avenues for astrophysical research.
